Your entire body is made of living tissue. This tissue is made up of tiny cells. You can’t see these cells with the naked eye. Normal cells reproduce (divide) in a controlled way. When you have cancer, some cells become abnormal, changing shape. These cells may divide quickly and spread into other parts of the body.
Several tests are used to measure the size of a tumor and learn how far it has spread. This is called staging. The stage of your cancer will help determine your treatment. Based on American Cancer Society guidelines, the stages of breast cancer are:
Stage 0. The cancer is noninvasive. Cancer cells are found only in the ducts (ductal carcinoma in situ).
Recurrent breast cancer. When the cancer returns despite treatment.
A screening mammogram is an x-ray of the breast used to detect breast changes in women who have no signs of breast cancer. It usually involves two x-rays of each breast. Using a mammogram, it is possible to detect a tumor that cannot be felt.